August 16, 2017 Weekly Crop & Weather Update

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Below you will find the daily maximum and minimum air temperatures, growing degree units (GDUs), and 24-hour precipitation amounts for this week. These values are recorded at 8 AM and reflect the conditions for the previous 24-hour period (8 AM to 8 AM) at the Southern Research & Outreach Center, Waseca.

Date Max Air Temp (oF) Min Air Temp (oF) GDUs Precip. (inches)
Thursday, 8/10 71 61 16.0 0.18
Friday, 8/11 75 57 16.0 0.16
Saturday, 8/12 75 53 14.0 -
Sunday, 8/13 78 56 17.0 -
Monday, 8/14 74 59 16.5 0.24
Tuesday, 8/15 74 54 14.0 0.01
Wednesday, 8/16 71 57 14.0 0.22

A cool, cloudy, damp weather pattern settled into south central Minnesota this week. Temperature averaged 65.4 degrees which is 5 degrees cooler than normal. Rain was measured on 5 days this week but totaled only 0.81 inch or 0.31 inch less than normal. Growing degree units (GDUs) totaled 107.5 or 21% less than normal. GDU accumulation for the season remains slightly ahead of normal. Since May 1 we have accumulated 1876.5 GDUs which is 2% more than normal.

Last year this week was the beginning of record setting rainfall that cursed us through September. Temperature averaged 73.9 degrees and 5.4 inches of rain fell. Last year at this time we had accumulated 2034 GDUs.

Corn is in the R4 (dough) stage. Kernels have now accumulated about one-half their mature dry weight. With plenty of grain filling that needs to still occur, favorable growing conditions would help finish off what appears to be a very good corn crop in our area. Soybeans are in the R5 (beginning seed) stage. This is a critical time of the growing season for soybeans because flowering will stop and yield depends on how well the pods develop. Soybeans at this stage are still taking up nutrients from the soil along with redistributing material from the plant to fill pods. Favorable growing conditions are important now for pod fill.

The corn crop in our area looks very good and nitrogen deficiency symptoms are hard to find. The Minnesota Extension Service has written a piece on late season N application for corn. While it does not apply to this season it may be a good reference in years to come. The information can be found at this link: